1. Field of the Invention
The present invention relates generally to powered conveyor systems for continually transferring material from one point to another, particularly in the longwall coal mining industry. More particularly, the present invention comprises a conveyor system formed of a series of relatively short units which may be assembled together, with each unit containing a pair of rotary discs therein. Power is provided for rotating the discs, with the rotation of the discs transferring material from disc to disc along the conveyor run.
2. Description of the Related Art
Powered conveyor systems have universal application in the continuous transfer of material from one point to another, and have long been used in a number of different industries and environments. Most such conventional conveyor systems utilize a flat belt or belts driven by powered rollers, to convey the material from one point to another. Generally, this principle has proven to be reasonably durable and reliable for the conveyance of most goods and materials.
However, such conventional conveyor systems are pushed to the limit of their reliability when installed in some relatively harsh environments. An example of such is the coal mining industry, particularly in longwall underground mining. The longwall mining technique has been developed relatively recently, i.e., in the past few decades. In longwall mining, a mining machine advances laterally along the face of the coal seam, which may be on the order of a thousand feet in length. A longwall face conveyor system extends behind the mining machine, and parallel to the face of the seam and travel of the mining machine. Conventional longwall face conveyor systems are powered by endless runs of conventional link chains, and operate continuously to transfer tons of coal from the mining machine to the end of the longwall face and conveyor run, where the coal is transferred to another conveyor or to a coal skip for transport to the surface.
The problem with conventional chain driven conveyor systems is that even though they are constructed of extremely sturdy materials, they are still prone to shutdown primarily due to breakage of links in the chain drive mechanism. When a single link breaks, the conveyor line is shut down, which shuts down the entire mining operation until the conveyor system is repaired. Considering the lost time when such a conveyor system is down for maintenance and/or repair, and the expense of repairing such systems underground, it can cost a mining operation on the order of two million dollars per year to repair and maintain a longwall face conveyor having a one thousand foot run.
The present invention provides a solution to this problem by means of a longwall face conveyor system utilizing a completely different principle of operation. The present conveyor system is formed of a series of separate units or pans, with each pan preferably containing a pair of vaned rotary discs thereon. The pans are linked together to form a conveyor run of the desired length. The rotary discs may be powered by any of a number of different means, e.g., roller chain and sprocket assemblies, rotary shafts extending between each pan and disc, or electric or hydraulic motors, etc. The present rotary disc conveyor system is considerably more durable than conventional link chain driven conveyor systems, resulting in far less down time for the conveyor line. The present rotary disc conveyor system is particularly well suited for use in longwall coal mining, as noted further above, but may be used in virtually any environment where conventional conveyor systems are used.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 842,056 issued on Jan. 22, 1907 to John C. Barr, titled “Circular Floor Conveyor,” describes various embodiments of such circular conveyor systems. One embodiment incorporates multiple circular conveyors, but the conveyors include high peripheral walls and are separated into compartments by radial walls. These conveyors are not configured so much for the transfer of material from one to another, as for rotating the compartments for convenience in loading and unloading.
U.S. Pat. No. 2,415,201 issued on Feb. 4, 1947 to Erich R. Zademach et al., titled “Rotary Conveyor,” describes a single, circular conveyor having a toroid configuration. The conveyor surface thus does not extend completely across the span of the Zademach et al. conveyor, and no means is provided to link a series of such conveyors together in a synchronized drive system, as provided by the present rotary conveyor system.
U.S. Pat. No. 3,061,074 issued on Oct. 30, 1962 to Albert Musschoot, titled “Rotary Conveyor,” describes a single rotary disc for redistributing loose material from an input chute to an output chute. A diverter blade extends from the center to one edge of the disc, but the diverter blade is stationary relative to the rotary motion of the disc. No multiple discs having a synchronous drive system are disclosed by Musschoot.
U.S. Pat. No. 3,125,210 issued on Mar. 17, 1964 to Charles E. Sheetz, titled “Rotary Fruit Handling Apparatus,” describes a rotary distribution system which accepts articles from an overhead linear conveyor and distributes them to the periphery of the rotary devices. The only conveyor apparatus in the Sheetz machine is the overhead linear conveyor. Also, the Sheetz rotary elements are formed of two concentric discs separated by opposed spiral panels. The two concentric discs rotate at different speeds relative to one another. While Sheetz shows a pair of rotary disc assemblies in his machine, this is only to provide additional handling stations. The Sheetz machine is not truly a rotary conveyor, as it does not transmit material from one rotary assembly to another.
U.S. Pat. No. 3,360,104 issued on Dec. 26, 1967 to Herbert S. Winfield, titled “Parcel Distribution And Display System,” describes a carousel type airline passenger baggage handling system. Multiple carousels are shown, but each has a separate linear feed conveyor or chute, and none of the carousels communicate with one another. The carousels are stand-alone devices, rather than being set into a stationary unit or pan, as is the case with the present rotary disc conveyor system.
U.S. Pat. No. 3,848,724 issued on Nov. 19, 1974 to Wilber C. Belk, titled “Accumulator For Fragile Articles,” describes a single turntable having a depressed center, for accumulating articles. When sufficient articles have collected on the turntable, the table is tilted to dump the articles on a linear conveyor. Only a single rotary disc is disclosed by Belk, with no communication between plural rotary conveyor discs as provided by the present system.
U.S. Pat. No. 4,056,189 issued on Nov. 1, 1977 to Donald L. Freed, Jr., titled “Material Gathering Device For A Mining Machine,” describes a cutting drum disposed at the end of a boom, with a series of rotary discs positioned behind the cutting drum for transferring ore from the cutting drum to a conveyor extending along the boom. The rotary discs rotate in opposite directions to one another, in order to move the material centrally between the two center discs and laterally off the disc assembly to the conveyor. In contrast, the present system rotates all of the discs in the same direction, to convey material along the length of the present disc conveyor.
U.S. Pat. No. 4,078,649 issued on Mar. 14, 1978 to Ole Prydtz, titled “Conveyor Systems,” describes a complex mechanism for laterally displacing and rotating a series of conveyor discs in an overlapping assembly. The discs are sequentially displaced from their alignment as they are drawn along the conveyor chain, whereupon they rotate to displace an article(s) carried thereon until returned to their aligned positions. The present rotary disc conveyor system differs considerably from the Prydtz mechanism, in that in the present system: (1) the discs do not overlap; (2) each pair of discs is secured in its own pan or carrier, with a series of such pans or carriers being assembled together to form the conveyor of the present invention; (3) the discs are not displaced from their relatively fixed locations in their respective pans or carriers; (4) the discs of the present system rotate generally synchronously and continuously; (5) the present system includes a series of transfer vanes or blades atop each disc to urge the material from disc to disc; and (6) the present system is rotationally and directionally reversible.
U.S. Pat. No. 4,150,520 issued on Apr. 24, 1979 to Angelo Palmieri et al., titled “Device For Feeding Articles,” describes a device for sorting candies for distribution to a wrapping machine. The Palmieri et al. mechanism includes a pair of separated discs, but each of the discs has pockets for containing individual candies; such pockets teach away from the necessarily flat surfaces of the present discs. Moreover, a separate, relatively complex transfer mechanism is required to move candies from one disc to the other, unlike the present invention.
U.S. Pat. No. 4,159,055 issued on Jun. 26, 1979 to William R. Eberle, titled “Gathering Head,” describes a rotary disc transfer assembly for transferring ore dislodged from a seam by a mining machine, to a conveyor extending back of the mining machine. FIG. 8 of the Eberle issued patent illustrates a four disc assembly which more closely resembles the device of the Freed '189 U.S. Patent discussed further above, than it does the present invention. The same points of difference between the Freed mechanism and the present invention, i.e., the opposite direction of rotation of discs to either side of the center in order to convey ore laterally from the mining machine and gathering head to a conveyor extending generally normal thereto, are seen to apply here as well.
U.S. Pat. No. 4,662,508 issued on May 5, 1987 to Shinichi Inoue et al., titled “Product Feeding Device For Combination Weighing Machine,” describes a distribution system comprising a series of overlapping discs which distribute a product from one side thereof to the opposite side. A corresponding series of fixed fences assists in guiding the product across the line of discs, to the exit side. As in the cases of the devices of the Freed '189 and Eberle '055 U.S. Patents, the Inoue et al. mechanism is not truly a conveyor system, as it does not convey anything along the length of the overlapping discs, but rather transfers material from an entry side of the line of discs, to the opposite exit side. The fixed fences and lack of lateral retaining walls of the Inoue et al. mechanism render it incapable of conveying material along its length.
U.S. Pat. No. 4,671,707 issued on Jun. 9, 1987 to Stanley R. Vancelette et al., titled “Disc Transfer Mechanism For Electrical Component Assembly Machine,” describes an apparatus having a series of spaced apart discs thereon. The discs accept electronic components from one side of the line, and rotate through a partial revolution to place the components on a conveyor. The Vancelette et al. apparatus is thus not a conveyor per se, but rather a handling device for transferring objects from one side of the device to a conveyor on the opposite side, which then conveys the objects to another location. The Vancelette et al. mechanism thus has more in common with the transfer or handling mechanisms of the Freed '189, Eberle '055, and Inoue et al. '508 U.S. Patents, than it does with the present rotary disc conveyor system.
U.S. Pat. No. 5,535,999 issued on Jul. 16, 1996 to Anthony D. Ford, titled “Apparatus For Rotating A Flat Article Through A Desired Angular Orientation,” describes a conveyor system having a series of widely spaced discs extending from the plane thereof. As the discs travel along the bottom run of the conveyor, they grip articles carried on another conveyor therebelow. The discs are rotated through a partial revolution to align the carried articles as desired on the lower conveyor. The Ford conveyor mechanism thus more closely resembles the apparatus of the '707 U.S. Patent to Vancelette et al. than it does the present rotary disc conveyor system.
U.S. Pat. No. 5,634,545 issued on Jun. 3, 1997 to Roger D. Plumley, titled “Apparatus For Continuously Conveying Coal From A Continuous Mining Machine To A Remote Floor Conveyor,” describes a linear conveyor system formed of a series of interconnected endless linear belts. The assembly includes motive power for repositioning as desired. The Plumley apparatus is closely related to such mechanisms used in the coal mining industry at present. The present rotary disc conveyor system, in contrast, is configured to operate along the face wall of a longwall continuous mining operation, and convey coal to a linear conveyor for conveyance from the mine.
U.S. Pat. No. 5,927,468 issued on Jul. 27, 1999 to Carlo Corniani et al., titled “Method And Unit For Orienting Pump-Operated Caps,” describes a bottle capping machine. The machine includes a pair of wheels or discs which rotate opposite one another, and which grip bottles about the disc peripheries. No means is disclosed by Corniani et al. for conveying material atop a series of such discs.
U.S. Patent Publication No. 2002/96,934 published on Jul. 25, 2002, titled “Mining Machine And Method Of Mining,” describes a system wherein a continuous mining machine mines a roadway tunnel into the ore seam, with a pair of augers mining a series of tunnels lateral to the roadway. The coal is carried from the mine on conventional chain and belt conveyors. The publication makes no disclosure of any form of rotary disc conveyor system.
Japanese Patent No. 58-100,033 published on Jun. 14, 1983, titled “Coal Throwing In Device Of Storage Tank,” describes (according to the drawings and English abstract) a rotating conveyor system for distributing coal evenly within a cylindrical storage tank or container. The conveyor system itself is an extendible linear device, with no rotary disc components. However, the linear conveyor may be rotated about a vertical axis extending through the center of the tank, to distribute coal evenly about the sides of the tank rather than creating a mound of coal in the center of the tank.
Finally, German Patent No. 3,726,450 published on Mar. 2, 1989, titled “Device For Loading Saggers With Ceramic Material Or For Unloading The Ceramic Material From The Saggers,” describes (according to the drawings and English abstract) a linear and rotary conveyor system for use in the ceramics industry. “Saggers” (fireproof containers) are loaded with ceramic articles to be fired, and emptied after firing, by means of the conveyor system of the '450 German Patent Publication. However, the conveyor system uses only a single rotary component in making a 180° change of direction during the loading and unloading of the “saggers.” No continuous, linear conveyor system comprising a series of rotary discs is provided in the '450 German Patent Publication.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a rotary disc conveyor system solving the aforementioned problems is desired.